TW201546319A - Gas supply device, film forming apparatus, gas supply method, and storage medium - Google Patents

Abstract

A gas supply device for intermittently supplying raw material gas into a film forming process unit that includes a raw material container for accommodating a raw material, a carrier gas supply unit for supplying carrier gas to evaporate the raw material, a raw material gas supply path for supplying the raw material gas and the carrier gas into the film forming process unit, a flow rate detector, a flow rate regulating valve, a raw material supply and block unit for supplying and blocking the raw material gas into the film forming process unit, and a control unit for outputting a control signal for intermittently supplying the raw material gas into the film forming process unit.

Description

Gas supply device, film forming device, gas supply method, and non-transitory memory medium

The present invention relates to a flow rate adjustment technique for a raw material supplied to a film forming apparatus.

A method of forming a film on a substrate such as a semiconductor wafer (hereinafter referred to as "wafer") is a method of CVD (Chemical Vapor Deposition) to supply a gas (material gas) which is a film forming material to the surface of the wafer, and then The wafer is heated to adsorb the material gas to form a film; or an ALD (Atomic Layer Deposition) method is used to adsorb the atomic layer or the molecular layer of the material gas on the surface of the wafer, and then supply and oxidize/reduct the material gas. The reaction product is produced by reacting a gas, and the treatment is repeated to deposit a layer of the reaction product.

Here, in the film forming raw material used by the CVD method, the ALD method, or the like, the low vapor pressure is high. In this case, the material gas can be supplied to the raw material container containing the liquid or the solid raw material by the carrier gas. It is obtained by vaporizing a raw material in this carrier gas. However, the amount of gasification of the raw material varies depending on various major factors. As a main factor, there are individual differences in the temperature of the gasifier caused by the individual difference in the contact state between the device in which the gasifier is installed and the gasifier, and individual differences in the valves provided on the piping to which the raw material container is connected. Or the difference in the conductance of the piping due to frequent changes of the valve, and the reduction of the raw materials in the raw material container.

For the change in the gasification amount which is mainly caused by the temperature of the gasifier, the gasification amount can be measured after the gasifier is replaced, and the temperature correction can be performed or canceled according to the gasification amount. However, it is difficult to correct the gasification amount which is mainly caused by the decrease in the flow conductivity of the piping and the reduction of the raw material in the raw material container, and the main factors may cause the gasification amount to be changed, for example, about 4%. Hey. However, the change in the amount of gasification caused by this causes the properties of the film formed on the wafer to be different.

Further, in the ALD method and the CVD method, the raw material gas is intermittently supplied to the reaction container in which the wafer is stored, and the time from the supply of the raw material gas to the next supply of the raw material gas is sometimes stopped. Will be shorter. When the supply time of such a raw material gas is short, as described in the embodiment, it is difficult to detect the flow rate of the raw material supplied to the wafer. Under such circumstances, there is a need for a technique capable of suppressing a change in gasification amount among the above-mentioned main factors, and stabilizing the flow rate of the raw material supplied to the wafer each time the wafer is processed.

Further, there is known a technique for spraying a carrier gas (foaming) whose flow rate is adjusted by a first mass flow rate meter for a raw material liquid accommodated in an evaporation portion during film formation in a semiconductor manufacturing process. And the raw material liquid is evaporated, and the mass flow rate of the obtained mixed gas is measured by a mass flow meter, and the amount of the raw material liquid after vaporization is grasped according to the difference in mass flow rates of the carrier gas and the mixed gas. However, as described above, when the raw material gas is intermittently supplied and the supply time of the raw material gas is short, there is no corresponding technology.

[The problem that the invention wants to solve]

The present invention is directed to a technique for preventing supply of a raw material gas composed of a carrier gas and a raw material vaporized by the carrier gas to a substrate to be processed to form a film. The flow rate of the raw material of the substrate is unstable every time the substrate is processed. [Method of solving the problem]

In the gas supply device of the present invention, the raw material gas is intermittently supplied to a film formation processing unit that performs a film formation process on the substrate to be processed, and includes a raw material container for containing a liquid or a solid material, and a carrier gas supply unit for supplying a carrier gas for vaporizing or sublimating the raw material in the raw material container; and a raw material gas supply passage for supplying the raw material gas composed of the vaporized or sublimated raw material and the carrier gas to the film forming processing portion; The material gas flow rate detecting unit and the material gas flow rate adjusting valve are provided in the material gas supply path, the material gas supply/stop unit, and the supply/stop of the material gas to the film forming processing unit; and control And outputting a control signal to perform the following steps: In the first step, based on the flow rate of the carrier gas supplied from the carrier gas supply unit and the flow rate of the material gas detected by the flow rate detecting unit, Obtaining a flow rate of the raw material in the raw material gas, and obtaining an opening degree of the flow rate adjusting valve whose flow rate of the raw material is a set value; and a second step, in order to flow the flow The opening degree of the state where the acquisition of fixed opening degree adjustment valve for the raw material gas is intermittently supplied to the film formation processing unit, and the raw material gas is supplied / stop the supply portion of the execution / stop.

In the gas supply method of the present invention, the raw material gas is intermittently supplied to a film formation processing unit that performs a film formation process on the substrate to be processed, and the method includes the following steps: supplying a carrier gas to the raw material container containing the raw material, and using the raw material Gasification; supplying a raw material gas composed of the vaporized raw material and the carrier gas to the substrate to be processed from the raw material container via a raw material gas supply passage; and detecting flow by the raw material gas supply passage The measuring unit detects the flow rate of the raw material gas; and determines the flow rate of the raw material gas by the flow rate of the carrier gas supplied to the raw material container and the flow rate of the raw material gas detected by the flow detecting unit a flow rate of the raw material; adjusting an opening degree of the flow regulating valve provided in the raw material gas supply passage to adjust a flow rate of the raw material gas flowing through the raw material gas supply passage; and obtaining a flow rate adjusting valve whose flow rate of the raw material is a set value And the raw material gas is intermittently supplied to the film forming processing unit in a state in which the adjusting valve is fixed to the obtained opening degree, and the opening is performed. Supplying the raw material of the film processing section of the gas / stop; while on the substrate to be processed loaded portion of the film forming process, the implementation of the respective programs.

The memory medium of the present invention is a non-transitory memory medium that stores a computer program for a gas supply device that supplies a material gas to a film forming process in order to perform a film forming process on a substrate. The program includes steps for performing the gas supply method.

The memory medium of the present invention includes the gas supply device and the film formation processing unit.

Embodiment of the Invention

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Further, in the following detailed description, numerous specific details are set forth in the However, it will be apparent to those skilled in the art that the invention may be carried out without departing from the scope of the invention. In other instances, well-known methods, sequences, systems, or components are not described in detail in order to avoid obscuring the embodiments.

Hereinafter, a configuration example of the film forming apparatus 1 including the gas supply device of the present invention will be described with reference to Fig. 1 . The film forming apparatus 1 includes a film forming processing unit 11 that performs a film forming process on a substrate such as a wafer W by a CVD method, and a gas supply device 2 that supplies a material gas to the film forming processing unit 11.

The film processing unit 11 is a main body of a batch type CVD apparatus. For example, after the wafer boat 13 on which a plurality of wafers W are placed is loaded into the vertical reaction container 12, vacuum evacuation by a vacuum pump or the like is used. The portion 15 evacuates the inside of the reaction vessel 12 via the exhaust line 14. Then, the material gas is introduced from the gas supply device 2, and the wafer W is heated by the heating unit 16 provided outside the reaction container 12, thereby performing a film formation process.

The gas supply device 2 supplies a first monomer (for example, pyromellitic dianhydride (PMDA)) composed of a difunctional acid anhydride to each wafer W, and a difunctional amine. 2 monomers (for example ODA (4,4'-diaminodiphenyl ether)). These monomers react on the surface of the wafer W to form a polyimide film as an insulating film.

The gas supply device 2 includes a first gas supply system 21 for supplying the PMDA to the reaction container 12, and a second gas supply system 22 for supplying the ODA to the reaction container 12. The first gas supply system 21 includes a raw material container 3, a raw material PMDA containing the polyimine, and a gas supply source 41, and nitrogen (N ₂ ) gas is supplied as a carrier gas to the raw material container 3. Further, in addition to the N ₂ gas, the carrier gas may be an inert gas such as helium (He) gas.

Further, the first gas supply system 21 includes a material gas supply passage 42 , a carrier gas supply passage 43 , a gas flow passage 44 , and a gas supply passage 45 . The material gas supply passage 42 is connected to the reaction container 12 and the raw material container 3, and supplies the raw material gas (including the sublimated PMDA and the carrier gas) obtained from the raw material container 3 to the film formation processing unit 11. The carrier gas supply passage 43 is connected to the raw material container 3 and the gas supply source 41.

The raw material container 3 is a container for accommodating the solid raw material 31 (PMDA), and is covered by a sleeve-shaped heating portion 32 having a resistance heating element. For example, the raw material container 3 can increase or decrease the amount of power supplied from the power supply unit 34 based on the temperature of the gas phase portion in the raw material container 3 detected by the temperature detecting unit 33, whereby the temperature in the raw material container 3 can be adjusted. The set temperature of the heating unit 32 is set to a temperature at which PMDA is sublimated and does not decompose, such as 250 °C.

In the gas phase portion on the upper side of the solid raw material 31 in the raw material container 3, an opening is formed in which the gas nozzle 35 is carried, and the carrier gas supplied from the gas supply source 41 is introduced into the raw material container 3; and the nozzle 36 is withdrawn. For extracting the raw material gas from the raw material container 3. The carrier gas nozzle 35 constitutes the downstream end of the carrier gas supply passage 43; the extraction nozzle 36 constitutes the upstream end of the material gas supply passage 42. The material gas extracted from the raw material container 3 is supplied to the reaction container 12 via the material gas supply passage 42. The inside of the raw material container 3 is evacuated by the vacuum exhaust unit 15 via the material gas supply passage 42 and the reaction container 12 to maintain a reduced pressure environment.

The MFC (mass flow controller) 51 and the valve V1 are sequentially inserted into the carrier gas supply passage 43 toward the downstream side. The valve V2, the MFC 52, and the valve V3 are sequentially inserted into the material gas supply passage 42 toward the downstream side. The valve V4 is inserted into the gas flow path 44. The upstream end of the gas flow path 44 is connected between the MFC 51 and the valve V1 that carry the gas supply path 43, and the downstream end of the gas flow path 44 is connected between the valve V2 and the MFC 52 of the material gas supply path 42.

The MFC 53 and the valve V5 are sequentially inserted into the gas supply path 45 toward the downstream side. The upstream end of the gas supply passage 45 is connected between the gas supply source 41 and the MFC 51 in the carrier gas supply passage 43, and the downstream end of the gas supply passage 45 is connected to the downstream side of the valve V3 of the source gas supply passage 42. The function of the gas supply passage 45 and the MFC 53 is to dilute the raw material gas taken out from the raw material container 3 to a predetermined concentration by the N ₂ gas from the gas supply source 41 before being supplied to the reaction container 12.

The MFC 52 provided in the material gas supply passage 42 will be described with reference to the schematic configuration diagram of Fig. 2 . The MFC 52 has a main flow path 61 and a thin tube portion 62, and one end and the other end are connected to the main flow path 61, respectively. The tube walls of the upstream side position and the downstream side of the thin tube portion 62 are wound around the resistors 63 and 64, and a bridge circuit 65 and an amplifying circuit 66 are provided for flowing the thin tube caused by the gas flowing through the thin tube portion 62. The temperature change of the wall of the portion 62 is obtained as a change in the resistance value of each of the resistors 63 and 64, and is converted into a flow signal of the gas to be output. The flow signal is output to a control unit 4, which will be described later, and the control unit 4 measures the flow rate of the gas flowing through the MFC 52 based on the flow signal. That is, the MFC 52 is configured to have a thermal MFM (mass flow meter) as a flow detecting unit.

In the main flow path 61, a curved flow path 60 is formed on the downstream side of the connection position of the thin tube portion 62, and a valve (flow rate adjustment valve) 67 for adjusting the gas flow rate in the curved flow path 60 is provided. That is, the flow rate of the gas supplied from the MFC 52 is adjusted by the opening degree of the valve 67. The valve 67 includes an actuator 68 which is constituted by a piezoelectric element, and a diaphragm 69 which is deformed by the actuator 68. The control unit 4 supplies a control voltage to the actuator 68, and deforms the piezoelectric element as the actuator 68 in response to the supplied control voltage, thereby bending the diaphragm 69. The thus curved diaphragm 69 is indicated by a broken line in FIG. Due to the bending of the diaphragm 69, the curved flow path 60 is narrowed. That is, the opening degree of the valve 67 corresponds to the amount of bending of the diaphragm 69, and the opening amount of the valve 67 is controlled by the control voltage controlling the amount of bending of the diaphragm 69.

The MFCs 51 and 53 have the same configuration as the MFC 52. The MFC 51 controls the opening of the flow signal control valve 67 output from the MFC 51 so that the flow rate of the carrier gas flowing through the MFC 51 becomes a previously set value. The MFC 53 is also controlled so that the amount of gas supplied to the downstream side becomes a value set in advance. The control of MFC 52 is detailed later.

The second gas supply system 22 and the first gas supply system 21 have substantially the same configuration. In FIG. 1, the same reference numerals are given to the portions corresponding to the first gas supply system 21, and detailed description thereof will be omitted. However, the above-mentioned ODA of the liquid raw material is contained in the raw material container 3, and instead of PMDA, it is used as a raw material of polyimine. In order to distinguish from the raw material gas containing PMDA, the raw material gas composed of the vaporized ODA gas and the carrier gas supplied from the raw material container 3 to the reaction container 12 is referred to as a processing gas.

The film forming apparatus 1 (the film forming processing unit 11 and the gas supply device 2) having the above configuration is connected to the control unit 4. The control unit 4 is configured by, for example, a computer including a CPU and a memory unit (not shown), and outputs a control signal to each unit of the film forming apparatus 1 to perform the following operation: the wafer boat 13 is carried into the reaction container 12, and after evacuation The raw material gas is supplied from the gas supply device 2 to form a film, and the operation from when the supply of the raw material gas is stopped to when the wafer boat 13 is carried out is performed. By this control signal, the switching of each valve, the opening degree adjustment of each valve, and the flow control of each gas using each MFC are performed. In order for the film forming apparatus 1 to perform such an operation, a program in which the steps (command) group has been assembled is stored in the memory unit. The program is stored on a memory medium such as a hard disk, a compact disc, a magneto-optical disc, or a memory card, and then installed to a computer.

The control unit 4 controls the first and second gas supply systems 21 and 22, and alternately supplies the raw materials to the wafer W in the reaction container 12 from the first and second gas supply systems 21 and 22. The gas forms a polyimide film. The first gas supply system 21 is controlled by two kinds of conditions to supply the raw material gas into the reaction container 12. For convenience of explanation, the first aspect is set to the first control state and the second control state, respectively. When the material gas is supplied to the wafer W for the first time, the first gas supply system 21 is controlled by the first control state; and when the material gas is supplied after the second time, the first gas is controlled by the second control state. Supply system 21.

The flow rate of the carrier gas measured by the flow signal of the MFC 51 is set to Q1. The valve 67 of the MFC 51 is controlled so that this Q1 becomes a preset value set in advance. Further, the flow rate of the material gas measured from the flow signal output from the MFC 52 is set to Q3. The control unit 4 can calculate the PMDA flow rate (gasification flow rate of the raw material) Q2=Q3-Q1 from the flow rates Q1 and Q3. In the first control mode, the opening degree of the valve 67 of the MFC 52 is adjusted, and the vaporization flow rate Q2 of the raw material is set to a predetermined value. That is, the first control mode is feedback control, and the opening degree of the valve 67 of the MFC 52 is controlled based on the flow rate Q3 of the material gas and the flow rate Q1 of the carrier gas so that the vaporization flow rate Q2 of the raw material becomes a set value.

In the first raw material gas supply to the wafer W, the carrier gas is supplied to the raw material container 3 for a long period of time in order to stabilize the amount of PMDA vaporization (herein, vaporization including sublimation) at the time of supplying each raw material gas. Therefore, the supply time of the material gas in the reaction vessel 12 is set to be long. Therefore, in the first supply of the raw material gas, the carrier gas can be filled into the raw material container 3 in the supply of the raw material gas, and then the MFC 52 can be reached, and the amount of PMDA vaporization in the raw material container 3 can be stabilized. As a result, the value of Q3-Q1=Q2 from the start of the supply of the raw material gas to the lapse of a predetermined time can be highly accurately correlated with the PMDA gasification flow rate actually supplied to the reaction vessel 12, and further, as will be described later As shown in the figure, when the opening degree of the valve 67 of the MFC 52 is set to be fixed, Q3 and Q2 are stable. Therefore, by performing the above-described feedback control, the gasification flow rate Q2 can be made to coincide with the set value, and the gasification flow rate caused by the gasifier temperature, the pipe conductance, and the raw material consumption state described in the background art can be removed. The impact.

However, in the supply of the raw material gas after the second time, the supply time to the film formation processing unit 11 is set to be shorter than when the material gas is supplied for the first time from the viewpoint of increasing the productivity and preventing the waste of the raw material. As described above, when the supply time of the material gas is short, the supply time of the material gas is completed before the raw material container 3 is filled by the carrier gas of the MFC 51 and reaches the MFC 52. Therefore, the deviation between the vaporization flow rate Q2 of the raw material calculated by the above Q3-Q1 and the vaporization flow rate of the actual raw material becomes large, that is, even if the feedback control described above is performed, the actual PMDA cannot be obtained. The case where the gasification flow rate becomes the set value.

In addition, in the supply of the raw material gas after the second and subsequent times, the amount of PMDA vaporization in the supply of the raw material gas is unstable, and as described above, the carrier gas does not reach the MFC 52. Therefore, as will be described later. When the opening degree of the valve 67 of the MFC 52 is fixed, the Q3 and Q2 may continue to change during the supply time of the material gas. If the feedback control is performed for such continuously changing Q2, the flow rate of the PMDA actually supplied to the reaction vessel 12 will be different due to the responsiveness of the MFC 52 to the control signal of the valve 67. Specifically, it is a concern that the swing of the Q2 sometimes occurs and sometimes does not occur due to the responsiveness of the MFC 52, and the flow rate of the PMDA supplied to the reaction container 12 between the film forming apparatuses 1 is likely to be different. For the above reasons, it is not a good idea to perform feedback control of the valve 67 of the MFC 52 during the supply of the material gas after the second time.

Therefore, in the first supply of the raw material gas, in the execution of the first control aspect, the control unit 4 supplies the predetermined degree of time from the start of the supply of the raw material gas to the stable timing of the opening of the valve 67 of the MFC 52. The control voltage of the actuator 68 of the valve 67 is stored in the memory portion included in the control unit 4. On the other hand, when the material gas is supplied after the second time, the second control state continuously supplies the stored control voltage to the actuator 68, and the opening degree of the valve 67 of the MFC 52 is fixed. The raw material gas is supplied to the reaction vessel 12 in such a state that the opening degree is fixed.

As described above, in the second control aspect, the valve 67 is fixed in advance to an opening degree at which the desired vaporization flow rate Q2 can be obtained, and the opening degree of the valve 67 can be prevented from changing with the change of Q2. Thus, by fixing the opening degree of the valve 67, the flow rate of the PMDA supplied to the reaction vessel 12 is prevented from being excessively different from the expected flow rate, and the MFC 52 is prevented from responding to the control signal from the control unit 4. PMDA traffic is uneven. Further, as for the second gas supply system 22, the control of the first and second control states is not performed, and a predetermined amount of carrier gas is supplied into the raw material container 3 to vaporize the ODA, and the carrier gas is further supplied. The processing gas composed of the vaporized ODA is supplied to the wafer W.

Next, an example of a procedure for forming a polyimide film by the film forming apparatus 1 will be described using the program diagrams of FIGS. 3 to 11 . First, the wafer boat 13 carrying a plurality of wafers W is carried into the reaction vessel 12, and the reaction vessel 12 is heated by the heating portion 16 to a temperature at which the polyimide film is formed, for example, 100 ° C to 250 ° C, preferably 150 ° C. ~200 ° C (Figure 1 reference). Next, the pressure in the reaction container 12 is controlled to a predetermined degree of vacuum by the vacuum exhaust unit 15, and the wafer boat 13 is rotated around the vertical axis by a rotating mechanism (not shown).

The valve V5 of the first gas supply system 21 is turned on, and the N ₂ gas from the gas supply source 41 is supplied to the reaction container 12 via the gas supply path 45. This valve V5 is always set to the on state during the processing of the wafer W. Next, the valve V4 is opened to adjust the pressure of the flow path on the upstream side of the valve V4. At this time, the valves V1 and V2 are set to the closed state, and the supply of the carrier gas from the MFC 51 to the raw material container 3 is not performed (step S1, FIG. 3). In this step S1, the valve V3 can also be opened.

After the valve V4 is opened, for example, after 2 seconds, the valve V4 is closed and the valves V1 and V2 are simultaneously opened. After the valves V1 and V2 are opened for several seconds, the carrier gas is supplied from the MFC 51 to the raw material container 3. The flow rate of the carrier gas is controlled by the MFC 51 to a flow rate Q1 set in advance in the range of 50 to 300 Sccm. The carrier gas is supplied to the raw material container 3, and the PMDA is vaporized, and the raw material gas composed of the vaporized PMDA and the carrier gas flows from the raw material container 3 to the downstream side through the raw material gas supply passage 42 and is supplied from the gas. The N ₂ gas flowing in the passage 45 is diluted and supplied to the reaction vessel 12.

The control unit 4 obtains the flow rate Q3 of the material gas in the material gas supply passage 42 based on the flow rate signal output from the MFC 52 of the material gas supply passage 42, and calculates the vaporization flow rate Q2 of Q3-Q1=PDMA, and controls the MFC 52. The opening degree of the valve 67 is such that the Q2 is set to a flow rate set in advance in the range of, for example, 40 to 150 Sccm (step S2, Fig. 4). That is, in the step S2, the first control aspect described above is executed.

As described above, the supply of the raw material container 3 for carrying the gas continues for a long time, and the measured flow rate Q3 is stabilized, and the gasification flow rate Q2 calculated thereby is also stabilized, so that the control voltage to the valve 67 of the MFC 52 is fixed. When the valves V1 and V2 are turned on, for example, 40 seconds later, the control unit 4 stores the control voltage in the memory unit, and continuously outputs the control voltage to the MFC 52. That is, the opening degree of the valve 67 is fixed without adjusting the opening degree (step S3, FIG. 5). That is, in the step S3, the second control aspect described above is executed. The PMDA molecules contained in the material gas supplied to the reaction vessel 12 are deposited on the surface of the wafer W to form a PMDA layer.

After the control voltage is stored for, for example, 15 seconds, the supply of the carrier gas from the MFC 51 is stopped, and the valves V1, V2, and V3 are closed, and the supply of the material gas to the reaction container 12 is stopped. The valve V5 is continuously set to the on state, and the reaction container 12 is supplied with N ₂ gas. The raw material gas remaining in the reaction vessel 12 is blown off by the N ₂ gas, and is removed from the exhaust line 14. This blowing continues for 10 seconds (step S4, Fig. 6).

Thereafter, the valves V1, V2, V3, and V5 of the second gas supply system 22 are turned on from the closed state, and the carrier gas is supplied to the ODA of the raw material container 3. The ODA is vaporized, and the processing gas containing the carrier gas and the ODA gas is taken out from the raw material container 3, diluted with N ₂ gas from the gas supply path 45, and supplied to the reaction container 12 (step S5, FIG. 7).

The ODA in this process gas reacts with the PMDA on the surface of the wafer W to form a thin layer of polyimide. When the processing gas is supplied from the second gas supply system 22 for a predetermined period of time, the valves V1 and V2 are closed, the supply of the carrier gas to the raw material container 3 is stopped, and the supply of the processing gas to the reaction container 12 is stopped. On the other hand, the valves V3, V4, and V5 are turned on, and the reaction container 12 is supplied with N ₂ gas. The process gas remaining in the reaction vessel 12 is blown off by the N ₂ gas, and is removed from the exhaust line 14 (step S5', Fig. 8). When the N ₂ gas is supplied from the second gas supply system 22 for a predetermined period of time, the valves V3, V4, and V5 are closed.

Thereafter, the valves V1 and V2 of the first gas supply system 21 are opened, and after the valves are opened, the carrier gas is supplied to the raw material container 3 to vaporize PMDA. At this time, the MFC 51 is controlled to pass the carrier gas at the same flow rate Q1 as the above steps S2 and S3. The valve 67 of the MFC 52 becomes the opening degree obtained in the step S2. In addition, since the valve V3 constituting the supply/stop portion in the downstream side of the MFC 52 is in the closed state, the material gas is stored on the upstream side of the valve V3 (step S6, FIG. 9). In the step S6, the valve 67 of the MFC 52 is not subjected to the feedback control as described above, and the opening degree thereof is fixed, because the following can be prevented: if feedback control is performed, in the next step S7, in the reaction container At the moment when the supply of the material gas is started, the supply is started from the state in which the material gas is stopped, and the opening degree of the valve 67 is increased. That is, by fixing the opening degree, it is possible to prevent the opening degree from becoming excessive, and to cause a large flow rate of the material gas to flow into the reaction vessel 12.

When, for example, 3 seconds have elapsed after the valves V1 and V2 are opened, the valve V3 is opened, and the material gas is supplied to the reaction container 12 (step S7, FIG. 10). The opening of the valve 67 of the MFC 52 continues to be the degree of opening achieved. The PMDA supplied to the wafer W is deposited on the thin layer of the polyimide polyimide formed on the wafer W in the same manner as in the above steps S2 and S3. Similarly to step S3, after the valve V3 is turned on, for example, 15 seconds later, the supply of the carrier gas from the MFC 51 is stopped, and the valves V1, V2, and V3 are closed, and the supply of the material gas to the reaction container 12 is stopped. That is, this step S7 is a step of performing the same operation as the above-described step S3.

As explained in the second control aspect, in this step S7, the supply time of the material gas is short, and the difference Q2 between the flow rate Q3 measured by the MFC 52 and the flow rate Q1 of the carrier gas set by the MFC 51 is actual. The corresponding accuracy of the flow rate of the vaporized PMDA is lower than when the supply time of the raw material gas is long, and the calculated Q2 value is also unstable. Therefore, the feedback control of the valve 67 of the MFC 52 according to the Q2 is not performed, and the opening degree of the valve 67 of the MFC 52 is fixed.

After step S7, the steps of steps S4 to S7 are repeated. Fig. 11 is a timing chart showing the supply timing of the raw material gas containing PMDA and the processing gas containing ODA, and the steps of performing the above steps. As described above, by performing the respective steps, the material gas and the processing gas are repeatedly supplied to the reaction container 12 at intervals. When the process of supplying the raw material gas, the exhaust of the raw material gas, the supply of the processing gas, and the exhaust of the processing gas is one cycle, the cycle is repeated, for example, about 100 times. Thereby, the polyimine layer is laminated on the wafer W to form a polyimide film having a predetermined film thickness. Thereafter, the wafer boat 13 is carried out from the reaction container 12.

Next, when the wafer boat 13 on which the wafer W is placed is carried into the reaction container 12, the above-described series of steps from the step S1 are performed, and the polyimide film is formed as described above. That is, in step S2 subsequent to the step S1, the opening degree of the valve 67 of the MFC 52 is newly obtained, and in steps S3 and S7, the valve 67 is fixed to the opening degree. The reason for regaining the opening degree is as follows: as described above, if the raw material of the raw material container 3 is decreased, the amount of vaporization is changed, and the opening degree of the valve 67 for obtaining the vaporization flow rate Q2 of the raw material which becomes the set value also changes. . In other words, in the film forming apparatus 1, the above-described steps S1 to S7 are executed every time the wafer W is loaded.

According to the film forming apparatus 1, when the supply time of the raw material gas is set to be long, the raw material gas is supplied to the first cycle, and the flow rate Q3 of the raw material gas detected by the MFC 52 and the flow rate Q1 of the carrier gas set to the MFC 51 are calculated. The PMDA vaporizes the flow rate Q2, and obtains the opening degree of the valve 67 of the MFC 52 having the vaporization flow rate Q2 as a set value. On the other hand, in the second and subsequent cycles in which the supply time of the material gas is short, the valve 67 is fixed to the opening degree obtained in the first cycle to supply the material gas. These operations are performed each time the wafer W is carried into the reaction container 12. By supplying the material gas at the opening degree thus obtained, the flow rate of the vaporized PMDA supplied to the wafer W can be suppressed from deviating from the current flow rate, and by fixing the opening degree, the PDMA flow rate due to the responsiveness of the MFC 52 can be suppressed. Produce a bias. As a result, the vaporized PMDA flow supplied to the reaction vessel 12 per treatment can be stabilized. Thereby, it is possible to suppress the film quality of the polyimide film formed on the wafer W in each treatment.

In the second and subsequent cycles, the supply time of the material gas is 15 seconds in the above example, but it may be shorter, such as several seconds. In the above example, the second gas supply system 22 is also the same as the first gas supply system 21, and its operation can be controlled by the first control aspect and the second control aspect. The film-forming raw material is not limited to the above examples. For example, in the case of forming a polyimide film similarly to the above example, CBDA (1,2,3,4-cyclobutanetetracarboxylic dianhydride), CHDA (cyclohexane-1, 2, 4) can be used. , 5-tetracarboxylic dianhydride, etc. to replace PMDA. Further, NDA (5-carboxymethylbicyclo[2.2.1]heptane-2,3,6-tricarboxylic acid 2,3:5,6-dianhydride) or the like can be used instead of ODA. Further, the present invention is also applicable to a device using the ALD method.

The piezoelectric element constituting the actuator 68 has hysteresis. In other words, the control voltage (drive voltage) is lowered from the target voltage applied to the actuator 68 (the positive side voltage) to become the target voltage; and the voltage is smaller than the target voltage. When the voltage on the negative electrode side rises to the target voltage, the amount of bending of the diaphragm 69 is different. Therefore, even if the same control voltage is applied to the actuator 68, there is a case where the opening degree of the valve 67 is different. In order to prevent the deviation of the opening degree, the MFC 52 may be determined to be the target voltage when the voltage from the positive electrode side is lowered or the target voltage is raised from the negative electrode side voltage. The control voltage is applied in a manner. Which of the positive electrode side voltage and the negative electrode side voltage is the target voltage can be determined by performing the evaluation of the film forming apparatus 1 before the wafer W is processed.

Further, even if the control voltage applied to the valve 67 is fixed, the flow rate of the PMDA supplied to the reaction vessel 12 is changed due to the change in the opening degree of the valve 67 of the MFC 52 due to the change in the temperature around the MFC 52 in the film forming process. After that. In order to prevent this flow change, a temperature sensor may be disposed around the MFC 52, and a cooling mechanism may be provided to the MFC 52. The cooling mechanism can use, for example, a Peltier element or a cooling fan. The control unit 4 is configured to detect the ambient temperature by an output signal from the temperature sensor. During the cycle of performing the film forming process, when the detected ambient temperature exceeds the target value, the control unit 4 operates the cooling mechanism to lower the ambient temperature below the target value.

In the above example, after the opening degree of the valve 67 of the MFC 52 is obtained, the opening/closing of the valve V3 on the secondary side of the MFC 52 is performed under the condition that the opening degree of the valve 67 is fixed to control the raw material of the reaction vessel 12. Gas supply/stop. In addition to this, when the supply of the material gas to the reaction vessel 12 is stopped, the valve 67 of the MFC 52 is closed to block the supply of the material gas to the reaction vessel 12; when the source gas is supplied to the reaction vessel 12 The valve 67 is opened to make the obtained opening degree, and supply/stop of the material gas to the reaction container 12 is performed.

In the above example, the MFC 52 is provided as a machine integrally constituted by a valve 67 (for adjusting the flow rate in the material gas supply path 42) and an MFM (for detecting the flow rate in the material gas supply path 42). The MFM and the valve 67 are not integrally formed, and the MFM and the valve 67 each configured may be provided in the material gas supply passage 42. The actuator 68 of the valve 67 is not limited to the piezoelectric element, and an electromagnetic coil or a motor or the like may be used. The valve 67 is not limited to the diaphragm type valve as long as the valve opening degree can be adjusted. It is also possible to use a needle valve or a butterfly valve. [Experiment 1]

A film forming apparatus (experimental film forming apparatus) having a configuration similar to that of the film forming apparatus 1 described above is used to record the flow rate Q1 of the carrier gas measured during the processing of the wafer W, and the raw material, in accordance with the above embodiment. The flow rate of the gas Q3. Further, the vaporization flow rate Q2 (= Q3-Q1) of the raw materials calculated from Q1 and Q3 is also recorded. However, this experimental film forming apparatus differs from the film forming apparatus 1 in that MMF 52 is used instead of MFC 52, and the flow rate Q3 of the material gas is measured using the MFM. Unlike the MFC 52, this MFM does not have a valve 67 that changes the opening degree by the control signal of the control unit 4. Therefore, in the experiment 1, in the step S2 in which the film forming apparatus 1 is used to carry out the embodiment, since the opening degree of the valve 67 of the MFC 52 cannot be adjusted, the valve 67 is used in steps S2, S3, and S7. The opening degree is fixed to be the same opening degree for processing.

Figure 12 is a graph showing the changes in Q1, Q2, and Q3. The flow rate Q1 is indicated by a broken line; the dotted line indicates the flow rate Q2; the solid line indicates the flow rate Q3. The horizontal axis in the graph indicates the time (unit: second) elapsed from the scheduled time, and the vertical axis indicates the flow rate of the gas (unit: Sccm). In addition, the figure shows the sequence of performing each of the above steps S. However, as described above, step S7 is a step of performing the same operation as step S3. In the above example, step S7 performed in the second and subsequent steps is referred to as step S7 for convenience, but in Fig. 12, for this step S7 is also shown in step S3. The reason why Q2 and Q3 rise temporarily after the start of step S2 and then fall is due to the fact that the raw material gas stored in the flow path flows into the MFM by opening the valve. After this fall, Q2 and Q3 gradually rise and then stabilize, and the period (step T1 shown in FIG. 12) required from the start of step S2 to the stabilization of Q2 and Q3 is about 20 seconds.

There are two reasons why Q2 and Q3 rise and are not stabilized from the start of step S2 to the lapse of 20 seconds. As described above, it takes time for the carrier gas whose flow rate is measured by MFC51 to reach the MFM, and the amount of PMDA gasification is stable. It takes time until now. In this way, after 20 seconds from the start, since Q2 and Q3 are stable, MFC52 is set instead of MFM, and by performing feedback control when it is so stable, Q2 is made to coincide with the set value, and it is possible to suppress each of them as described in the background art item. The change in gasification flow caused by the main factors.

Further, in the second step S3 (step S7), Q2 and Q3 rise transiently shortly after the start of the step. The rise of Q2 and Q3 is caused by the fact that the raw material gas accumulated in the pipeline on the upstream side of the MFM flows into the MFM in step S6. Q2 and Q3 fall after such a rise, and are stabilized after 4 seconds from the start of the step. In Fig. 12, the period from the start of the step to the stabilization is indicated by T2. As can be seen from the graph, in the second step S3, unlike step S2, the Q2 and Q3 stable periods are short. As described in the embodiment, if the feedback control of the opening degree of the valve 67 of the MFC 52 is performed in accordance with the changed Q2, the Q2 is changed due to the responsiveness of the MFC 52. That is, a deviation is generated between the film forming apparatuses 1. Therefore, in the second and subsequent steps S3 (step S7), the feedback control is not performed, and as shown in the embodiment, the opening degree of the valve 67 to which the MFC 52 is fixed is effective.

According to the present invention, the flow rate of the raw material in the material gas is obtained based on the flow rate of the carrier gas and the flow rate of the material gas, and the opening degree of the flow rate adjusting valve whose flow rate of the raw material is set to a set value is obtained. Then, the flow rate adjustment valve is fixed at the obtained opening degree, and the material gas is intermittently supplied to the film formation processing unit. These operations are performed when the substrate to be processed is carried into the film formation processing unit. Thereby, it is possible to suppress the flow rate of the raw material supplied to the substrate to be processed from being unstable every time the treatment of the substrate to be processed is performed. As a result, the properties of the film formed on the substrate to be processed can be suppressed from being different.

The embodiments disclosed above are illustrative and not limiting. In fact, the above embodiments can be embodied in various forms. Further, the above-described embodiments may be omitted, substituted, or changed in various forms without departing from the scope of the appended claims. The scope of the invention is to be construed as being limited by the scope of the appended claims.

1‧‧‧ film forming device
2‧‧‧ gas supply device
3‧‧‧Material containers
4‧‧‧Control Department
11‧‧‧ Film Processing Department
12‧‧‧Reaction container
13‧‧‧The boat
14‧‧‧Exhaust line
15‧‧‧vacuum exhaust
16‧‧‧ heating department
21‧‧‧1st gas supply system
22‧‧‧2nd gas supply system
31‧‧‧ solid materials
32‧‧‧ heating department
33‧‧‧Temperature Detection Department
34‧‧‧Power Supply Department
35‧‧‧ carrying gas nozzle
36‧‧‧Without nozzle
41‧‧‧ gas supply source
42‧‧‧Material gas supply path
43‧‧‧ Carrying gas supply path
44‧‧‧ gas flow path
45‧‧‧ gas supply path
51~53‧‧‧MFC
60‧‧‧bend flow path
61‧‧‧main road
62‧‧‧Small tube department
63, 64‧‧‧ resistors
65‧‧‧Bridge Circuit
66‧‧‧Amplification circuit
67‧‧‧Valves
68‧‧‧Actuator
69‧‧‧Separator
W‧‧‧ wafer
V1~V5‧‧‧ valve
Q1‧‧‧Flows carrying gases
Q2‧‧‧ Gasification flow of raw materials
Q3‧‧‧Flow of raw material gas

The attached drawings show the disclosed embodiments and are included as part of the specification, together with the general description and the details of the embodiments described below.

Fig. 1 is a view showing the overall structure of a film forming apparatus including a gas supply device of the present invention.

Fig. 2 is a schematic configuration diagram of a mass flow controller in the gas supply device.

Fig. 3 is a process chart according to the film forming apparatus.

Fig. 4 is a process chart according to the film forming apparatus.

Fig. 5 is a process chart according to the film forming apparatus.

Fig. 6 is a process chart according to the film forming apparatus.

Fig. 7 is a process chart according to the film forming apparatus.

Fig. 8 is a process chart according to the film forming apparatus.

Fig. 9 is a process chart according to the film forming apparatus.

Fig. 10 is a process chart according to the film forming apparatus.

Fig. 11 is a timing chart showing the supply timing of various gases according to the film forming apparatus.

Fig. 12 is a graph showing the gas flow rate measured using a device substantially the same as the film forming apparatus.

1‧‧‧ film forming device

2‧‧‧ gas supply device

3‧‧‧Material containers

4‧‧‧Control Department

11‧‧‧ Film Processing Department

12‧‧‧Reaction container

13‧‧‧The boat

14‧‧‧Exhaust line

15‧‧‧vacuum exhaust

16‧‧‧ heating department

21‧‧‧1st gas supply system

22‧‧‧2nd gas supply system

31‧‧‧ solid materials

32‧‧‧ heating department

33‧‧‧Temperature Detection Department

34‧‧‧Power Supply Department

35‧‧‧ carrying gas nozzle

36‧‧‧Without nozzle

41‧‧‧ gas supply source

42‧‧‧Material gas supply path

43‧‧‧ Carrying gas supply path

44‧‧‧ gas flow path

45‧‧‧ gas supply path

51~53‧‧‧MFC

W‧‧‧ wafer

V1~V5‧‧‧ valve

Q1‧‧‧Flows carrying gases

Q2‧‧‧ Gasification flow of raw materials

Q3‧‧‧Flow of raw material gas

Claims (8)

A gas supply device that intermittently supplies a material gas to a film formation processing unit that performs a film formation process on a substrate to be processed, and includes: a material container that contains a liquid or a solid material; and a carrier gas supply unit that supplies a carrier gas for vaporizing or sublimating the raw material in the raw material container; and a raw material gas supply passage for supplying the raw material gas composed of the vaporized or sublimated raw material and the carrier gas to a film forming processing unit; The gas flow rate detecting unit and the material gas flow rate adjusting valve are provided in the material gas supply path, the material gas supply/stop unit, and the supply/stop of the material gas to the film forming processing unit, and the control unit. When the control signal is output to carry the substrate to be processed into the film formation processing unit, the following steps are performed: In the first step, the flow rate of the carrier gas supplied from the carrier gas supply unit is detected by the flow rate The flow rate of the raw material gas detected by the part is obtained, and the flow rate of the raw material in the raw material gas is obtained to obtain the flow regulating valve having the flow rate of the raw material as a set value. In the second step, in order to fix the opening degree of the flow rate adjusting valve to the state in which the opening degree is obtained, the material gas is intermittently supplied to the film forming processing unit, and the material gas supply/stop unit is used. The supply/stop of the material gas. The gas supply device according to claim 1, wherein the carrier gas supply path between the carrier gas supply unit and the raw material container is set to set the flow rate of the carrier gas to a set value. The mass flow controller for gas holding, the flow rate of the carrier gas used in the first step is the set value of the mass flow controller. The gas supply device according to claim 1, wherein the flow rate detecting unit of the material gas and the flow rate adjusting valve are constituted by a mass flow controller for the material gas. A film forming apparatus comprising: the gas supply device according to claim 1; and the film forming processing unit. The film forming apparatus of claim 4, further comprising: a gas supply unit that supplies the processing gas different from the material gas to the film forming processing unit alternately. A gas supply method in which a raw material gas is intermittently supplied to a film formation processing unit that performs a film formation process on a substrate to be processed, and a method of supplying a carrier gas to a raw material container containing a raw material to vaporize the raw material a raw material gas composed of the vaporized raw material and the carrier gas is supplied to the substrate to be processed from the raw material container via a raw material gas supply passage; and a flow detecting portion provided in the raw material gas supply passage Detecting the flow rate of the raw material gas; determining the raw material in the raw material gas according to the flow rate of the carrier gas supplied to the raw material container and the flow rate of the raw material gas detected by the flow detecting unit Flow rate; adjusting an opening degree of a flow rate adjusting valve provided in the material gas supply passage to adjust a flow rate of the material gas flowing through the material gas supply passage; and obtaining an opening degree of the flow rate adjusting valve whose flow rate of the raw material becomes a set value And in order to fix the adjustment valve to the obtained opening degree, the raw material gas is intermittently supplied to the film forming processing unit to perform a material gas. Supplying the film-forming section of / stop; the substrate to be processed in the loaded portion of the film forming process, the implementation of the respective programs. The gas supply method according to claim 6, further comprising the step of: supplying a processing gas different from the material gas to the film forming processing unit alternately. A non-transitory memory medium for storing a computer program for a gas supply device for supplying a material gas to a film forming processing portion for performing a film forming process on a substrate, the program comprising The step of the gas supply method of the sixth item.